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9/22/2017 12:11:25 AM
Posted: 8/17/2005 7:57:06 PM EDT
What kind of uppers can fit the sp1 lower. I've seen advertised uppers that say they have the "small hole" My sp1 doesn't have the quick release front pin but rather the flat head screw type. I doubt I will replace my upper as its all original but I was curious about the "small hole" ad.
Link Posted: 8/17/2005 8:34:39 PM EDT
Small hole pivot pin is .250 diameter. Any upper with small hole pivot pin should fit and even the large hole .312 diameter will fit too using an adapter pivot pin.

You're lucky to have an SP1. My first AR was a Colt SP1 back in '71.

I wish I haven't sold it to buy an AR-15A2 back in the mid 80's.
Link Posted: 8/18/2005 2:25:33 PM EDT

Originally Posted By otbexige:
What kind of uppers can fit the sp1 lower. I've seen advertised uppers that say they have the "small hole" My sp1 doesn't have the quick release front pin but rather the flat head screw type. I doubt I will replace my upper as its all original but I was curious about the "small hole" ad.



You are probably referring to the CDNN "SP1 Upper" ad. Those uppers are in fact M16A1 uppers, not SP1 uppers. Maybe they are just afraid to advertise them for what they really are.
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